Each year, millions of people suffer from upper respiratory tract infections (URI or URTI) predominantly caused by virus infections. About 30 to 40% of cases are caused by rhinovirus infections. Other viruses include the coronavirus, para influenza virus, adenovirus and enterovirus. Another source of infection is bacterial attack, in part as second infection. URI involve the upper respiratory tract, i.e. nose, sinuses, pharynx or larynx and commonly include diseases such as tonsillitis (inflammation of the tonsils), otitis media, rhinitis (inflammation of the nasal mucosa), rhinosinusitis or sinusitis (inflammation of the nares and paranasal sinuses, including frontal, ethmoid, maxillary, and sphenoid), nasopharyngitis (rhinopharyngitis or the common cold, causing inflammation of the nares, pharynx, hypopharynx, uvula, and tonsils), pharyngitis (inflammation of the pharynx, hypopharynx, uvula, and tonsils), epiglottitis or supraglottitis, (inflammation of the superior portion of the larynx and supraglottic area), laryngitis—Inflammation of the larynx, laryngotracheitis (inflammation of the larynx, trachea, and subglottic area) and tracheitis (inflammation of the trachea and subglottic area). More than 200 rhinoviruses are known for causing URI. Depending from the area, the normal risk for developing URI ranges from less than 10 episodes per human individual per year in most industrialized countries up to several hundred episodes per human individual per year in some African an Asian countries. The overall risk in Central America, Africa and Asia, is at about 100 episodes. In some areas, predominantly at the eastern African coast and in Central Asia, the risk can reach a level of approx. 200 episodes per year or more.
Viruses and bacteria causing URI are mainly spread from person to person through airborne droplets that are sneezed out or coughed up by an infected person. In some cases, viruses and bacteria can be spread when a person touches an infected surface (e.g., doorknobs, countertops, telephones) and then touches parts of the body comprising mucous membranes such as nose, mouth, or eyes. As such, these diseases are most easily spread in crowded conditions such as schools. Although most people recover fully, URI borne sick days cause an enormous damage to the economy each year. Among high-risk populations, such as those with other medical conditions (such as diabetes or cancer) or a weakened immune system, seniors, or very young children, in rare cases even death can be a consequence of URI. Peak times for colds are at the start of school and kinder garden in the fall, in mid-winter, and again in early spring. In industrialized western countries having a high medical and hygiene standard children catch approximately up to 8 colds per year, adults catch roughly 4 colds per year, and seniors about 2 colds per year. Total number of URI episodes might be a little bit higher. People infected with an influenza or cold virus become contagious 24 hours after the virus enters the body (often before symptoms appear). Adults remain infectious (can spread the virus to others) for about 6 days, and children remain infectious for up to 10 days.
Common prevention means against URI's include simple frequent hand washing, general behavior such as coughing or sneezing into sleeves, and vaccinations, which are not recommended for children less than 6 months, people who have an egg or chicken protein allergy, an allergy to any of the ingredients of the vaccine, a history of allergic reactions to the flu vaccine, or in case of acute illness.
Thus, there is a need to provide further prevention means against URI's, preferably against rhinovirus infections and more preferably against common cold.
Arabinogalactan, for example from Echinacea or larch, have been reported by Yale et al. (Arch. Intern. Med. 2004, 164, 1237-1241) and Turner et al. (AAC, 2000, 44, 1708-1709) to stimulate the immune system without reference to consequences to real diseases.
Nothing in the state of the art indicates that an arabinogalactan extract from larch is capable of effectively reduce the risk in catching an URI, preferably a disease caused by a rhinovirus or more preferably a common cold in real subjects.
Arabino galactane (also referred to arabinogalactan, larch arabinogalactan, galactoarabinin, larch fiber or larch gum; CAS: [9036-66-2]), is a highly branched polysaccharide having a molecular weight between 15000 to 60000 Daltons that is composed of galactose units and arabinose units (arabinogalactan) in the approximate ratio of 6:1 (Scheme 1). Expediently, the botanical source is from Larix laricina (eastern larch) or Larix occidentalis (western larch). Arabinogalactan from larch usually contains a certain amount of polyphenols. Typically polyphenols are present at approx. 1 to 4 wt-%, more preferably at approx. 2 wt-%. Larch arabinogalactan is approved by the United States Food and Drug Administration (FDA) as a GRAS (Generally Recognized As Safe) affirmed direct food additive. A commercially available form of arabinogalactan is ResistAid™, which is an extract from larch bark and/or wood (chips or sawdust) (Larix ssp.)
Structural formula:
